Not sure that is really true based on the data. Remember, Moore's law says the number of transistors in an IC doubles every two years, which doesnt necessarily mean a doubling of performance. For a while in the 90's, performance was also doubling every two years, but that was largely due to frequency scaling.
A lot of the new processes have not had the same cost reductions. Also, some increase in transistor count is due to physically larger chips. Also, you have “Epyc Rome” on that graph, which actually isn’t a single chip but uses chiplets.
Yeah and after you have a working $30B fab, how many people are going to follow you to build one?
The first one built will get cheaper to run every year - it will pay for itself by the time a second company even tries to compete. The first person to the "final" node will have a natural, insurmountable monopoly.
You could extract rent basically forever after that point.
I don't think we'll see a final node in our lifetimes. Improvements are slowing down and will become a trickle, but that doesn't mean research stops entirely.
Consider other mature technology, like the internal combustion engine. ICEs have been improved continuously, though the changes have become marginal as the technology matured. However, if research and improvements on ICEs ends entirely it's not because the technology has been fully explored but because they're obsoleted by electric cars.
I thought the drivers of cost are lots of design work, patents, trade secrets etc. involved with each process. If there’s a “final” node, those costs should decrease over time and eventually become more of a commodity.
